Date: Tue, 05 Nov 1996 00:31:14 GMT
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<TITLE>CS/ECE 752 - Homework #2</TITLE>
<center>
<h2>CS/ECE 752: Advanced Computer Architecture I<P>
<P>
Prof. Mark D. Hill <P>
T.A. Jeff Shabel <P>
<P>
Due: Thurs, Oct. 10<P><P></h2></center>

Pertains to Chapter 5 of the text (Hennessy and Patterson, Computer 
Architecture: A Quantitative Approach, Second Edition, 1996).  You should 
work alone.  <B>No late assignments will be accepted.<P>

Problem II.1</B><P> <I>(8 points) Using a trace-driven cache
simulator.</I> Use <code>dinero</code> to examine a direct-mapped 16K-byte
unified cache with 16-byte blocks (use the default for other cache
options) using trace fragment <code>SPEC92/085.gcc.din.Z</code>.  For more
info, read <code>dinero.man</code> and <code>README</code>.  All files are
in directory <code>/p/course/cs752-markhill/public/software/dinero</code>. 
Do not copy the trace file, since it is almost 4MB.  You might want to do
some test runs with the first 50K references (-z50K) instead of waiting
for the full simulation.  Do not believe these results too much, since you
are using only one trace fragment.<BR>

<DL>
<DD>(a) What is the miss ratio
of the direct-mapped 16K-byte unified cache with 16-byte blocks?  What is
the effective access time assuming 5.0 ns to access the cache and a 100.0
ns miss penalty?<P> 

<DD>(b) Use the assumptions of part (a) except change
the block size to 32 bytes.  What is the new miss ratio?  The larger block
size could hurt the miss penalty.  At what miss penalty will this new
cache have the same effective access time as the cache in part (a)?  Round
your answer to the nearest 0.1ns.  Ignore cycle-time boundaries.<P>

<DD>(c) Use the assumptions of part (a) except change the associativity to
2-way.  What is the new miss ratio?  The larger associativity could hurt
the time to access the cache.  At what cache access time will this 2-way
cache have the same effective access time as the cache in part (a)?  Round
your answer to the nearest 0.1 ns.  Ignore cycle-time boundaries.<P>

<DD>(d) When this trace fragment begins, the true contents of the cache in
part (a) are unknown.  What is the maximum relative error in the miss
ratio caused by this lack of knowledge?  Explain how you got your
answer.<P> </DL> <P> <B>Problem II.2</B>


<P> <I>(6 points)</I> H&P problem 5.14.<P> 

For part (b), plot the miss ratios for both a direct-mapped and
fully-associative instruction cache with block size of 32 bytes.  Use
<code>SPEC92/085.gcc.din.Z</code> as you did in problem #1. Vary the cache
size from 64 bytes to 4K bytes.  Plot both sets of data on the same graph. 
Highlight the point at which the cache stops consistently exhibiting this
behavior as described in the book. 


